Explorer crashes

Can anyone help me with this, please. I was in the process of converting a movie from MP4 to AVI on my desktop and Explorer all of the sudden crashes. It then continues to restart and crash several times before it finally freezes my desktop. I restarted Windows Vista and explorer crashes and restarts over and over again upon start up. I have no way of using the start menu, right click won't work because of explorer, I only have one profile to access my computer, and there's a file on my desktop that I believe is causing Explorer to crash, but no way of deleting it. Is there anyway to create another profile or access the files on my desktop without going through Explorer?